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About mnich7

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  1. One of the most well known track and field events is the long jump. This event is where an athlete sprints as fast as they can toward a line then jump into a sand pit. Several simple kinematic concepts are displayed in this event. Firstly the distance traveled by an object is proportional to the velocity of an object. This translates to the long jump in that the faster the person is moving as they approach the point where they have to jump, the farther they will travel. Also the length of the jump will be determined by the angle the jumper makes with respect to the ground. The ideal angle for this is 45 degrees, because this produces an ideal balance between velocity going in the x-direction and the y-direction. Therefore any good long jumper will have both good spped as they approach their jump as well as the skill to propel themselves at a 45 degree angle to the ground in order to produce the maximal distance out of their jump.
  2. In soccer the power of your shot can be the difference between a very good goal and a shot the goal keeper having no problem with the shot. But what goes into creating a more powerful shot? What determines this is the amount of torque one can create when you move your leg in the cyclical movement when striking a soccer ball. In the equation, T = F * r , you are clearly able to see that the amount of torque created by your shot is determined by the length of your leg that you are pivoting around in a partial circular motion. This brings to the soccer legend, Zlatan Ibrahimovic. He stands at 6' 5" much taller then most all soccer players. As well as a tremendous amount of skill, what sets him apart as an incredible player is his physical attributes. The longer leg that he has to strike the ball creates more torque in the circular motion of his leg. He may have the same amount of force being put into the shot however because torque is directly proportional to radii, Zlatan can create an extremely powerful shot relative to his peers.
  3. Super cool concept!!
  4. Wish I had one of those warp drives!!
  5. Fluid dynamics is the study of how liquids behave while they are in motion. The study of this can become very complicated for many reasons. Fluids can be have steadily or with turbulence. In steady flow, the fluid passing a given point maintains a steady velocity. For turbulent flow, the speed and or the direction of the flow varies. In steady flow, the motion can be represented with streamlines showing the direction the water flows in different areas. The density of the streamlines are directly proportional with its velocity. Fluids can be compressible or in compressible. This is the major difference between liquids and gases, because liquids generally are in compressible, meaning that they don't change volume much in response to a pressure change; gases are compressible, and will change volume in response to a change in pressure. Also, Fluid flow can be rotational or irrotational. Irrotational means it travels in straight lines; rotational means it swirls. The dynamics of fluid and defining it movement can be very complex for many reasons.
  6. When jumping over a hurdle in a race, many factors determine the faster runner. Obviously, taller people have an easier time with this but what is the reason for this? When a shorter person has to jump over a hurdle and literally jump to clear the hurdle a large time is spent in the air. This is wasted time that taller folks don't necessarily have worry about. When a person with longer legs clears a hurdle, they don;t actually jump. They merely open up their legs to clear the hurdle while their upper body remains in the same position with respect to the ground in the Y direction. This is a major advantage because when smaller people have to jump over the hurdle, they take a parabolic path that adds small amounts of time every hurdle they go over a hurdle.
  7. Lifting weights heavily depend on the type of person lifting. When a person squats, part of the motion forms a circle. The longer your legs are the larger the radius of this circle will be formed. When Jake DeMersman squats with his short stubby legs, he doesn't have to produce as much force as a longer legged person like myself. torque is proportional to the radius of the circle. Therefor when Jake squats, less torque is pulling up on him when he pushes back up on a squat. Also in terms of potential energy, Energy is proportional to the height of a certain mass. Therefore when i literally have to bring the weight a longer distance, a greater change in energy is required. When i squat there is a greater torque and more energy is required. Jake may squat more than me yet this may not be the best test of strength in legs.
  8. You have seen an object resting on another object in a way that doesn't seem to entirely make sense based upon what your used to seeing and you basic knowledge of how things should act. Generally this is to do with the center of mass being somewhere unexpected. When several objects are attached, they balance on their center of mass. In the image below, it doesn't seem to entirely make sense without an understanding of canter of mass. Although this doesn't seem like it, the center of mass of this system is right on the plane of the cup, however, it looks as though the center of mass is in a different place. A center of mass cannot be assumed without knowledge of the mass displaced in the object. An object may look as though mass is displaced evenly throughout but the center of mass will not be found in the middle as you would expect because mass is not evenly distributed. Center of mass is definitely a tricky subject in physics.
  9. Catching a football like pros is no easy task, especially when you have some of the hardest throwing quarterbacks in the world. A football of an NFL quarterback can be close to 60 mph(26m/s) , weighing roughly .4kg. This creates a momentum of roughly 10 kg times meters per second. this number may not seem large until it is coming toward you with 11 defenders making sure you don't catch that ball. In order to stop that ball you must apply just as great of a force back at the ball while squeezing hard enough to keep the ball in your hands. Doing this is always easier said than done. NFL receivers really do have a difficult job to do.
  10. When you kick a soccer ball your leg puts kinetic energy in the ball. Also when you kick a soccer ball the ball deforms for an instant. The energy going into the collision is the energy of your foot plus some stored energy in the ball. The energy coming out of is the movement of the ball plus some minuscule heat energy. Due to the deformity in the ball as well as the conservation of energy, the ball actually travels faster than your foot. it is commonly thought in the world of soccer that are taller or larger soccer player will produce a faster shot, this is not the case and it turns out to be the opposite of this theory. The velocity of the ball equals the velocity of the leg multiplied by the fraction of the mass of the leg over the total mass of the leg and the ball, multiplied by (1 + e). e being the coefficient of restitution, which is a constant measure by the seed the ball bounces up compared to the speed it hits the ground with. By the logic of this equation, when a smaller mass is applied, a smaller kicker should be able to kick a soccer ball faster. The kicking of a soccer ball is very complex and may not be as simple as it seems.
  11. if you watch most all NFL quarterbacks, they have a tight spiral on the ball. What is the reason for this? You might think that the motion of a football is a simple motion buy it is defiantly not. When you throw a football, if you throw it well, it will have somewhere between 400-600 RPM's. This spin creates a gyroscopic torque on the ball. The benefit of this spiral has to do with angular momentum and the atmosphere of the earth. If we played football on the moon you wouldn't ever see any person throw a ball with a spiral because it would have no the thick atmosphere of earth, there are air resistance forces that oppose movement. By throwing a ball in a spiral, it hold a consistent orientation through out its path, for the most part. This allow the quarterback and the receiver to easily predict the path of the ball to certain extent. A non spinning ball may be even to travel further than a spinning ball however, the accuracy trad off when thrown without a spiral is great.
  12. Lightning, just like everything, can be explored with a physics explanation. Lighting is primarily cased by the electrostatic build up in clouds. Its turns out that the bottom of the cloud ends up becoming negatively charged when lighting occurs. The explanation of why this occur is still somewhat unknown to modern science. Once the bottom of the cloud becomes very negatively charged, electrons seek the nearest positively charged object. This ends up being the ground. The electrons of the bottom of the cloud move down to the ground, and form what we see as large streaks of lighting. The reason lighting may strike a tree is that when one area of the ground is closer to the clouds than the est of the ground, it causes the electrical field to be concentrated in that one area. Even something like lighting has a practical physics explanation. Source:
  13. The ancient practice of testing who can throw something the furthest still exists today. We know it today as the Olympic event of the shot put. Though some may think that the distance someone can throw a shot put is only determined by strength, this is not the case, much skill goes into this event. Firstly the throwers gain rotational kinetic energy before the throw by spinning around as they approach their throw. Rotational kinetic energy is defined by an equation such that rotational kinetic energy is proportional to angular velocity squared. Therefore by spinning before the trow can greatly increase the distance of a throwers distance on their throw. This energy is transferred to the shot put on its release. Also the throwers must be sure to maintain the perfect angle of 45 degrees as this will yield the farthest throw due to the fact that when a right triangle is formed, the longest base of the triangle is created when there is a 45 degree angle to the horizontal. This translates to a maximum distance for the thrower. Shot put is much more than just strength.
  14. Wow!! Wouldn't want to get hit by one of those.
  15. Almost everyone has watched at least some NFL football, but not everybody understands what makes some players better than others, or why certain types of players are put in certain areas of the football field. Turns out football in many ways football is a game that heavily involves momentum. Momentum is defined by the simple equation: P=mv. There is a direct relationship between momentum and velocity as well as a direct relationship between momentum and mass. In most cases the most massive players of a team are found right on the line of scrimmage, no further than inches away from the biggest and most massive players of the other team, on the other side of the line of scrimmage. These players are known as the offensive and defensive linemen. Why are the biggest player found on the line of scrimmage? One major factor in creating momentum is increasing velocity, however, in the short space between the offensive and defensive linemen accelerating enough for velocity to bear a large enough factor on a player's momentum is unlikely.The other factor in the momentum of that player is the mass of that player, however the mass of a player takes no time to build up like velocity does, therefore a more massive player can create more momentum in a shorter space. For a linemen, generating more momentum decides who will push who backwards and separates a good or bad player. Another example of momentum in football would be in the infamous Rob Gronkowski. Love him or hate him he a great football player and largely because of the simple rules momentum. Gronk weighs roughly 265 pounds and can move at speeds unparalleled to anyone in the NFL of his mass. Once he catches a pass he is already moving at top speed. This combined with he size allows him to generate momentum unlike any other player in the NFL. In order to stop him from moving you need to match his momentum in the opposite direction, which generally takes more than one person to do. His rare skill set separates him as a great player. Simple rules of physics are found heavily in the game of football.